I have tested my memory a little with memtest, and no error.
But went I try with OCCT to test I always got error... on different core!
The thing is that I know that the overclock that I do don't need an increase in voltage.
You know I just play safe if everything is okay.
If I try on the stock clock I need to enable spread spectrum (It work!), otherwise I got error.

So where the hell could come those Electromagnetic Interference?
I will try to ''shield'' the surface of my waterblock with a plastic cover and on the heatsink that I putted on my southbridge.
I use non-conductive coolant by the way.

Yes, It was stable before at the same place! Same room!
Tested this processor with OCCT high priority until 3,7 ghz at 1,41 volts if I remember correctly.
Was fully stable on stock voltage until 3,4 ghz.

Now that I have installed all my watercooling stuff

Could it be that my case is opened on bold side? that I got PSU wire on my desk?